Satire has been a form of humorous writing for hundreds of years. Featured in early newspapers as well as many novels throughout history, satire is characterized by sarcasm and irony. The topics are usually subjects that authors feels so strongly about that they want to make fun of them and pick them apart.
Exaggerate a situation way beyond the norm. Take a popular celebrity, focus on a few major faults, and enlarge these faults beyond measure until they seem completely ridiculous. This will draw more attention to the negative aspects of that celebrity that people worship so much. You might make a certain body part bigger or have a famous alcoholic actress drink an amount of alcohol that is impossible to consume.
Mimic Great Pieces of Literature
Take a serious piece of literature and create your own novel, making fun of the original. This was done with the novel, "Gone With the Wind" when Alice Randall came out with her parody, "The Wind Done Gone." Another classic, "The Catcher in the Rye" by J.D. Salinger was parodied by satirical author Dan Greenburg who wrote "Catch Her in the Oatmeal."
Take a situation that everyone knows about and place it in a setting that is totally abnormal and out of place. This is especially helpful when creating satire about politicians. For example, in "Animal Farm," George Orwell uses barnyard animals to take on the characters of famous communists with both hilarious and disturbing results. For example, turning the president of the United States into a little girl with blonde pigtails would be considered very atypical.
Everyone would love to see their boss in a maid's uniform. Take a hierarchy and reverse its order for a humorous effect. For example, you could take a corrupt corporation and turn the CEO into a vending machine distributor for the break room soda can machine. Corrupt and rich business people are not popular in the United States, so this will be sure to intrigue others if you do it right.